1. Field of the Invention
This invention generally relates to electrochemical batteries and, more particularly, to a battery anode comprised of antimony (Sb) electrochemically active materials on an aluminum current collector.
2. Description of the Related Art
Rechargeable batteries are known to include at least one positive current collector and at least one negative current collector to support electrode materials that, once immersed in an electrolyte, participate in the electrochemical charge storage reactions. The charge storage occurs as a result of faradaic reactions at both the anode and cathode. Conventionally, both the positive and negative current collectors in a lithium-ion or sodium-ion battery are configured as flat metal foils or plates, referred to as current collectors [1]. The electrode materials are usually physically deposited on these current collectors. The current collectors collect the charges generated during discharging processes, and to permit the connection of the electrodes to an external power source during recharge. The charge transfer reactions and electrolyte decomposition in the proximity of the current collectors usually result in corrosion behavior at the metallic surface of the current collectors during cycling. Specifically, on the negative electrode side, Li-ion or Na-ion intercalation can occur, i.e., metallic alloys are formed upon taking the Li or Na ions [2]. Internal mechanical stress is therefore built up on the current collectors, which deforms and stretches the metal foils or plates. This stress is followed by pulverization of the current collectors and dissolution of the exposed current collector surface, which leads to an entire cell failure due to a drastic rise of internal resistance, rapid degradation of cell performance, and even internal shorting within current collectors and rapture of cell case.
To suppress such corrosion behavior and potential hazards, the choice of current collectors in Li-ion battery configurations is limited to copper (Cu) on the negative (anode) side and aluminum (Al) on the positive (cathode) side in non-aqueous electrolytes. High-quality metal foils and plates are required, and other less costly but corrodible metal species are preferably avoided. To further achieve a high power density and longer battery life, there have been attempts to treat the current collectors to diminish corrosion, for instance, by introducing non-corrodible metal or carbon coatings onto current collectors. However, substantial quantities of noble metals such as platinum, gold, or silver are needed in this scheme to ensure long-term robustness, which leads to significant increases in the material and manufacturing cost, and complexity in the final battery cells.
Conventionally, Cu has represented the only economically viable and practical solution as a negative electrode current collector in Li-ion and Na-ion batteries. However, care must be taken to prevent over-discharging the battery cells, which is a condition that results in Cu current collector degradation. In addition, certain types of active materials and electrolyte additives have a deleterious effect on Cu current collectors. For example, intermetallic alloy-based active materials (e.g., antimony) and alkaline salts (e.g., caesium salts) may alloy with Cu electrochemically.
Previously disclosed is a Na-ion battery design consisting of an Al current collector with carbonaceous anode materials [3,4]. However, an Al anode structure incorporating carbonaceous material is not capable of handling high current density when used with a non-aqueous electrolyte, which compromises the rate capability and power output of the battery device.
It would be advantageous if an anode could be fabricated with an Al current collector, capable of long life and high current densities, for use in a non-aqueous electrolyte battery.    1) T. R. Jow, Rechargeable Sodium Alloy Anode, U.S. Pat. No. 4,753,858.    2) A. H. Whitehead and M. Schreiber, Current Collectors for Positive Electrodes of Lithium-Based Batteries, J. Electrochem. Soc., 2005, 152, A2105-A2113.    3) S. Ohmori and T. Yamamoto, Sodium Ion Battery, US 2012/0021273A1.    4) S. Ohmori and T. Yamamoto, Sodium Ion Battery, EP 2413416A1.    5) A. Darwiche, C. Marino, M. T. Sougrati, B. Fraisse, L. Stievano and L. Monconduit, Better Cycling Performances of Bulk Sb in Na-Ion Batteries Compared to Li-Ion Systems: An Unexpected Electrochemical Mechanism, J. Am. Chem. Soc., 2012, 134, 20805-20811.    6) M. He, K. Kravchyk, M. Walter and M. V. Kovalenko, Monodisperse Antimony Nanocrystals for High-Rate Li-Ion and Na-Ion Battery Anodes, Nano Lett., 2014, 14, 1255-1262.    7) C. W. Bale, E. BBelisle, P. Chartrand, S. A. Decterov, G. Eriksson, K. Hack, I. H. Jung, Y. B. Kang, J. Melancon, A. D. Pelton, C. Robelin, and S. Petersen, FactSage Thermochemical Software and Databases—Recent Developments, Calphad, 2009, vol. 3, 295-311, (http://www.crct.polymtl.ca/fact/documentation/SGTE/SGTE_Figs.htm).